Semiconductor heterojunction devices based on SiC

Abstract

A Si (1-x) M x C material for heterostructures on SiC can be grown by CVD, PVD and MOCVD. SIC doped with a metal such as Al modifies the bandgap and hence the heterostructure. Growth of SiC Si (1-x) M x C heterojunctions using SiC and metal sources permits the fabrication of improved HFMTs (high frequency mobility transistors), HBTs (heterojunction bipolar transistors), and HEMTs (high electron mobility transistors).

1. A semiconductor device, comprising:
 a Si (1-x) M x C heterojunction formed on a SiC substrate, wherein M is Al or In and x is greater than 0 and less than 1, and wherein the heterojunction comprises a Si (1-x) M x C or SiC channel layer, a SiC or Si (1-x) M x C barrier, respectively, on top of the channel layer, and a n+SiC layer or n+Si (1-x) Ge x C, respectively, on top of the barrier layer. 
 
     
     
       2. The semiconductor device of  claim 1 , wherein the heterojunction is formed from doped (001) SiC. 
     
     
       3. The semiconductor device of  claim 1 , wherein x is about 0.06. 
     
     
       4. The semiconductor device of  claim 1 , wherein the Si (1-x) M x C heterojunction comprises a Si (1-x) M x C layer with a thickness of about 12 μm. 
     
     
       5. The semiconductor device of  claim 1 , wherein M is Al. 
     
     
       6. The semiconductor device of  claim 1 , wherein M is In. 
     
     
       7. The semiconductor device of  claim 1 , wherein x is 0.0001 to 0.1. 
     
     
       8. A semiconductor device, comprising:
 a SiC substrate; 
 an epitaxial film of Si (1-x) M x C formed over the substrate, where M is Al or In and x is greater than 0 and less than 1; 
 a SiC or Si (1-x) Ge x C layer, formed over the Si (1-x) M x C film; and 
 at least one transistor structure formed over the epitaxial film. 
 
     
     
       9. The semiconductor device of  claim 8 , wherein the transistor structure comprises a high frequency mobility transistor, a heterojunction bipolar transistor or a high electron mobility transistor. 
     
     
       10. The semiconductor device of  claim 8 , wherein x is about 0.06. 
     
     
       11. The semiconductor device of  claim 8 , wherein the epitaxial film is formed from doped (001) SiC. 
     
     
       12. The semiconductor device of  claim 8 , wherein the epitaxial film of Si (1-x) M x C has a thickness of about 12 μm. 
     
     
       13. The semiconductor device of  claim 8 , wherein a SiC buffer layer is formed between the substrate and the epitaxial film. 
     
     
       14. The semiconductor device of  claim 8 , wherein a SiC buffer layer and an SiC channel layer are formed between the substrate and the epitaxial film. 
     
     
       15. The semiconductor device of  claim 8 , wherein M is Al. 
     
     
       16. The semiconductor device of  claim 8 , wherein M is In. 
     
     
       17. The semiconductor device of  claim 8 , wherein x is 0.0001 to 0.1. 
     
     
       18. A semiconductor device, comprising:
 a Si (1-x) M x C heterojunction formed over a base substrate, wherein M is Al, Ge or In, x is 0.0001 to 0.1, the base substrate is SiC; and 
 a n+SiC or n+Si (1-x) Ge x C layer formed over the SiC/Si (1-x) M x C heterojunction, 
 wherein the semiconductor device includes no substantially Si-only layers.